1. Field of the Invention
The present invention relates generally to condoms, more specifically to abbreviated condoms, and most particularly to methods of manufacturing abbreviated condoms.
2. General Background
Abbreviated condoms are distinguished over conventional condoms by a much shorter, abbreviated, length. Conventional condoms are of sufficient length to encase the entirety of most erect penises including all of the shaft. Abbreviated condoms are of much shorter length intended to enclose just the head of an erect penis while leaving the shaft exposed in order to retain sensitivity and thereby encourage use of the condom. Both types of condom are intended to retain seminal fluid from ejaculation in order to prevent undesired pregnancy and more importantly, as many other types of contraceptives are available, to prevent transmission of sexually transmitted diseases (STDs) between sexual partners for which purpose condoms are the only effective means known.
Abbreviated condoms, in contrast to conventional, full length condoms, differ in two major aspects: (a) means of retaining the condom in position during use; and (b) providing a reservoir for the seminal fluid. Conventional condoms possess sufficient length and volume to utilize an elastic band about the open bottom for sealing the structure against leakage of seminal fluid and provide an inherent reservoir for the seminal fluid resulting from ejaculation. There is no need for a separate reservoir structure in a conventional condom and no need for means other than the elastic band at the open bottom of the condom for securing the condom during use. Abbreviated condoms require, in contrast to conventional full length condoms, a separate distinct reservoir, as well as a particular means of securing the condom in position during use which will prevent inadvertent displacement.
A review of the basic structures employed by abbreviated condoms in addressing these two fundamental problems is given below.
Prior Art
Two different basic forms of reservoirs and two different basic means of retaining an abbreviated condom in position during use are known in various forms in the prior art. An expansible area located in the cleft between the bilateral lobes of the glans penis is one type of reservoir. An expansible structure located directly in front of the opening of the urethra is another basic approach. Either type of reservoir is theoretically independent of the two basic approaches known in the prior art for retention of an abbreviated condom in position during use but an anatomically accurate analysis of the head of an erect penis reveals a correlation between these two aspects and exposes many of the difficulties in the prior art in addressing the problem of retention particularly.
One basic approach to a retention means is similar to that utilized by conventional, full length, condoms: use of an elastic band which, in contrast to the elastic band on a conventional condom, is typically intended to be located behind the glans penis in the sulcus thereby taking advantage of the relative increase in elevation from the shaft to the glans which occurs immediately in front of the sulcus. This approach is disadvantaged, however, by the fact that the elevated ridge immediately in front of the sulcus, which is quite pronounced on the back and top of the head of an erect penis, diminishes to practically nothing at the forward and bottom. This ridge also angles downward and forward which anatomical attribute is often neglected in the structure of many abbreviated condoms of the prior art which erroneously assume radial symmetry.
Use of an elastic band as a retention means for an abbreviated condom is hence hindered by the actual anatomical variance of the glans penis from radial symmetry. If this anatomical variance is observed and the elastic band is left as circular the area underneath the cleft and between the forward lobes of the glans penis may be utilized as a reservoir. This approach is found in U.S. Pat. No. 6,035,854 issued Mar. 14, 2000 to the present inventor, Rory P. Blake, which reference also contains a more detailed review of the prior art with regard to specific references relating to abbreviated condoms. One disadvantage of this approach, however, is the fact that this area beneath and below the bilateral glans is particularly sensitive for which reason it is preferably left exposed.
Another basic approach to retaining an abbreviated condom upon the head of an erect penis which can leave the particularly sensitive area beneath and in between the bilateral lobes of the glans penis is to utilize adhesive. Ideally, the application of an appropriate adhesive about the interior perimeter of an abbreviated condom will retain the same in position during use in a structure which only encloses the head of an erect penis, leaving the particularly sensitive area beneath and in between the bilateral lobes of the glans penis exposed. Nearly all of the prior art, with the notable exception of U.S. Pat. No. 6,035,854 issued Mar. 14, 2000 to the present inventor, assumes radial symmetry in the structure of the head of an erect penis and hence utilizes a radially symmetric abbreviated condom structure which renders the use of adhesive applied to the interior perimeter of an abbreviated condom defective with regard to sealing the same against transmission of bodily fluids including seminal fluid. In brief, unless the true anatomical structure of the head of an erect penis is taken into account the means of retaining an abbreviated condom upon the same is considered less than likely to succeed.
Statement of Need
Location of an expansible reservoir at the tip of an abbreviated condom is problematic for another reason. Several known prior art references utilize an accordion or concertina fold type structure for an expansible reservoir located at the tip. Theoretically this is perhaps ideal but there is no known method of manufacture for such a structure which is considered economically feasible. The assumption of radial symmetry, moreover, which has been demonstrated above to hinder effective means of retention of an abbreviated condom upon the head of an erect penis, is further seen to greatly simplify the method of manufacture. Conventional condoms are typically manufactured by dip molding and machining of the mold for the same is greatly simplified with the assumption of radial symmetry which, owing to the size of these condoms, does not present any problems with regard to retention of the same upon an erect penis. An anatomically accurate abbreviated condom, however, preferably does not assume radial symmetry.
Molding of an anatomically accurate abbreviated condom is considered problematic. With conventional tooling which assumes radial symmetry there is no hindrance to removing the condom from the interior mold structure. An anatomically accurate condom requires an anatomically accurate mold and not only is this unknown in the prior art but if it existed the interior mold structure would resist removal of the condom during manufacture because of the complex curves possessed of the bilaterally symmetric but radially unsymmetric lobes of the glans penis which are considered to characterize any head of any penis erect or flaccid. A need is therefore recognized for an economic manufacturing method for the production of anatomically accurate abbreviated condoms which conform to, and therefore possess, complex curves which are not radially symmetric.
Objects of the Invention
The encompassing object of the principles relating to the present invention is the provision of an economic method of manufacturing an anatomically accurate abbreviated condom possessing bilaterally symmetric but radially unsymmetric complex curves.
An auxiliary objective of the principles relating to the present invention is the provision of an economic method of manufacturing an anatomically accurate abbreviated condom possessing bilaterally symmetric but radially unsymmetric complex curves utilizing dip molding.
A first ancillary objective of the principles relating to the present invention is the provision of an economic method for the application of adhesive during production of an anatomically accurate abbreviated condom possessing bilaterally symmetric but radially unsymmetric complex curves.
A second ancillary objective of the principles relating to the present invention is the provision of an economic method for the application of an adhesive backing strip during production of an anatomically accurate abbreviated condom possessing bilaterally symmetric but radially unsymmetric complex curves.
A second auxiliary objective of the principles relating to the present invention is the provision of an economic method of manufacturing an anatomically accurate abbreviated condom possessing bilaterally symmetric but radially unsymmetric complex curves having an effective adhesive which is also readily removable.
A third ancillary objective of the principles relating to the present invention is the provision of an economic method of manufacturing an anatomically accurate abbreviated condom possessing bilaterally symmetric but radially unsymmetric complex curves having an effective adhesive which covers only a circumferential band.
Principles Relating to the Present Invention
Regardless of whether injection or dip molding is utilized a rather sophisticated form must be machined which accurately reflects the anatomy of the head of an erect penis. In the case of dip molding one interior positive form mold is concerned which must have an exterior which essentially mimics or reflects, accurately, the actual anatomical shape of the head of an erect penis. In the case of injection molding this positive form is the core and the matching or congruent exterior mold is a slightly larger negative of the same form. The form itself in any case is, as mentioned earlier, fully sculptured and includes complex curves which impede release from the interior positive form required of molding an anatomically accurate abbreviated condom in any manner.
This type of form requires machining with use of a computer guided milling machine using appropriately shaped milling heads which requires a computer program to direct the motion of the tool head during machining generated from a three dimensional computer graphic model. The generation of this model is essentially art and is not considered feasible unless the anatomy of the glans penis is fully appreciated by the artist generating this model. It is not possible, in other words, if the bilaterally lobed fully sculptured complex curved form of the head of an erect penis is simplified as being radially symmetric.
In achievement of the objectives given above it is first considered that the complex curves involved impose an undercut to the positive form which impedes release of the product in manufacture and that use of synthetic, polymeric, materials as opposed to natural latex exacerbates this impediment but is preferred for several reasons. Effective prevention of the transmission of STDs including HIV during sexual activity is the primary reason. Natural latex generally does not provide as effective a barrier against transmission as polymeric materials. A second reason is that significant, widespread, allergies to natural latex have developed in the human population in the last twenty-five years which phenomenon is largely credited, along with the increased incidence of STDs including HIV, with the replacement of latex by polymeric material having elastic qualities, i.e. elastomers, for the manufacture of condoms in recent years.
It is suggested that the impediment posed by the undercut of the complexly curved surfaces necessary be addressed with a positive mold form which possesses a bore and at least one aperture in communication therewith through which positive pressure can be introduced. This expands the product and lifts the same off the positive mold form. It is further considered that a circumferential adhesive layer is desired to ensure the prevention of fluid transmission and that a backing strip for the adhesive is desirable.
This backing strip necessarily has some rigidity and must be held flush against the positive mold form in order to ensure interior disposition. A perforated circumference of location and dimensions appropriate for the dimensions of the backing strip disposed about the positive mold form is suggested through which negative pressure can be applied. A shallow relief in the exterior surface of the positive mold of the thickness of the backing strip is also recommended for the purpose of ensuring interior disposition of the backing strip.
Negative pressure applied through the bore of the positive mold form to this perforated circumference retains the backing strip in correct disposition during application of an adhesive layer upon the exterior surface of the same, curing of the adhesive layer, coating the positive mold form with liquid polymeric material having elastic qualities, i.e. liquid elastomer, and curing of the liquid elastomer into the solid sheath product at which time the pressure is reversed and the finished product is lifted off the positive mold form.
It is further desired that the adhesive utilized be readily removed from the penis after use without causing pain and this essentially requires an adhesive which loses its adhesive qualities under readily obtained circumstances. It is suggested that a water soluble adhesive be utilized for this purpose which is sensitive to isotonic solution and hence maintains adhesion in contact with all bodily fluids. Tap water can be used to dissolve the adhesive layer for easy and comfortable removal of the condom after use while the tonicity of bodily fluids assures adhesion during use. Sulfopolyester adhesive is particularly recommended which is cured with ultraviolet (UV) radiation.
It is also particularly suggested that the positive mold form be coated with liquid elastomeric in a bath and that adhesive be applied in a directed dispersion, i.e. with a spraying operation, with the backing strip held by negative pressure through the perforated circumference. It is suggested that a simple reservoir be located directly in front of the urethra opening and that the perforated circumference, which locates the backing strip and adhesive, be located immediately behind the corona of the glans penis upon the margin adjacent the open end of the abbreviated sheath.